Leaned deswirl vanes behind a centrifugal compressor in a gas turbine engine

ABSTRACT

A compressor includes a deswirl assembly to improve aerodynamic coupling with the combustor. The assembly includes an annular housing and a plurality of vanes. The annular housing includes an inner and an outer annular wall disposed concentric to each other, and a flowpath defined therebetween. The plurality of vanes is disposed in the flowpath in a substantially annular pattern. Each vane has a leading edge, a trailing edge, a convex surface, and concave surface, and each of the convex and concave surfaces extends between the leading and trailing edges. Additionally, each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall. The vanes preferably have a uniform axial cross section for ease of manufacturing.

TECHNICAL FIELD

The present invention relates to a gas turbine engine and, moreparticularly, to a deswirl assembly having leaned deswirl vanes for usein the gas turbine engine.

BACKGROUND

A gas turbine engine may be used to power various types of vehicles andsystems. A typical gas turbine engine includes a fan section, acompressor section, a combustor section, a turbine section, and anexhaust section. The fan section induces air from the surroundingenvironment into the engine and accelerates a fraction of the air towardthe compressor section. The compressor section compresses the pressureof the air to a relatively high level and directs the air to thecombustor section. A steady stream of fuel is injected into thecombustor section, and the injected fuel is ignited to significantlyincrease the energy of the compressed air. The high-energy compressedair then flows into and through the turbine section, causingrotationally mounted turbine blades therein to rotate and generateenergy. The air exiting the turbine section is exhausted from the enginevia the exhaust section, and the energy remaining in the exhaust airaids the thrust generated by the air flowing through a bypass plenum.

In some engines, the compressor section is implemented with acentrifugal compressor. A centrifugal compressor typically includes atleast one impeller that is rotationally mounted to a rotor andsurrounded by a shroud. When the impeller rotates, it compresses andimparts tangential velocity to the air received from the fan section andthe shroud directs the air radially outward into a diffuser. Thediffuser decreases the radial and tangential velocity of the air andincreases the static pressure of the air and directs the air into adeswirl assembly. The deswirl assembly includes an annular housinghaving a plurality of straight radially extending vanes mounted thereinthat straighten and reduce the tangential velocity component of the airflow before it enters the combustor section. The combustor section insome engines is implemented with an axial through flow combustor thatincludes an annular combustor disposed within a combustor housing thatdefines a plenum. The straightened air enters the plenum and travelsaxially through the annular combustor where it is mixed with fuel andignited.

Recently, conventional deswirl assemblies have included downcantedoutlets to improve aerodynamic coupling between the diffuser andcombustor. However, it has been found that these deswirl assembliesgenerate greater flow angle variation across the span of the flowpath atthe deswirl vane leading edge and therefore may not adequately conditionair flow to a sufficiently low mach number in an acceptably efficientmanner unless the overall axial length and/or radial envelope of theassembly is increased. Because engines are continually designed to besmaller, the size increase may not be acceptable in newer aircraft. As aresult, the configuration of the deswirl assembly has had to beredesigned. One preferred configuration includes vanes that are shapedso that the vane can accept a large variation in air angle at itsleading edge. The vanes may also be configured such that the pressureside of each vane faces radially inwardly. However, although thisconfiguration optimizes airflow through the deswirl assembly,manufacture of the assembly is relatively time-consuming and costlybecause each vane may need to be individually formed and shaped.

Hence, there is a need for an improved downcanted deswirl assembly thatincludes a plurality of vanes that are configured to aerodynamicallycouple a centrifugal compressor and an axial through-flow combustor.Additionally, it is desirable for the deswirl assembly to be relativelyinexpensive and simple to manufacture. Moreover, it is desirable for thedeswirl assembly to suitably direct and condition the air flowing therethrough for optimal engine performance.

BRIEF SUMMARY

The present invention provides a deswirl assembly for receiving air flowfrom a diffuser. The deswirl assembly includes an annular housing and aplurality of vanes. The annular housing includes an inner annular wall,an outer annular wall disposed concentric to the inner annular wall, anda flowpath defined therebetween. The plurality of vanes is disposed inthe flowpath in a substantially annular pattern. Each vane has a leadingedge, a trailing edge, a convex surface, and concave surface, and eachof the convex and concave surfaces extends between the leading andtrailing edges. Additionally, each vane extends between and is angledrelative to the inner and the outer annular walls such that the concavesurface faces the outer annular wall and the convex surface faces theinner annular wall.

In one embodiment, and by way of example only, the deswirl assemblyincluding an annular housing, and a first and a second plurality ofvanes. The annular housing includes an inner annular wall, an outerannular wall disposed concentric to the inner annular wall, and aflowpath defined therebetween. The first plurality of vanes is disposedin the flowpath in a substantially annular pattern, and each vane has aleading edge, a trailing edge, a convex surface, and concave surface,each of the convex and concave surfaces extending between the leadingand trailing edges, each vane extends between and is angled relative tothe inner and the outer annular walls such that the concave surfacefaces the outer annular wall and the convex surface faces the innerannular wall and each vane has an axial cross section shape, and eachaxial cross section shape is substantially the same. The secondplurality of vanes is disposed in the flowpath in a substantiallyannular pattern downstream of the first plurality of vanes. Each vanehas a leading edge, a trailing edge, a convex surface, and concavesurface, each of the convex and concave surfaces extends between theleading and trailing edges, and each vane extends between and is angledrelative to the inner and the outer annular walls such that the concavesurface faces the outer annular wall and the convex surface faces theinner annular wall. Additionally, each vane of the second plurality ofvanes has an axial cross section shape, and each axial cross sectionshape is substantially the same.

In still another embodiment, a system is provided for aerodynamicallycoupling air flow from a centrifugal compressor to an axial combustor,where the compressor and combustor are disposed about a longitudinalaxis. The system includes a diffuser, a deswirl assembly, combusterinner and outer annular liners, a combustor dome, and a curved annularplate. The diffuser has an inlet, an outlet and a flow path extendingtherebetween, where the diffuser inlet is in flow communication with thecentrifugal compressor, and the diffuser flowpath extends radiallyoutward from the longitudinal axis. The deswirl assembly includes anannular housing and a plurality of vanes. The annular housing includesan inner annular wall, an outer annular wall disposed concentric to theinner annular wall, and a flowpath defined therebetween. The pluralityof vanes is disposed in the flowpath in a substantially annular pattern.Each vane has a leading edge, a trailing edge, a convex surface, andconcave surface, and each of the convex and concave surfaces extendsbetween the leading and trailing edges. Additionally, each vane extendsbetween and is angled relative to the inner and the outer annular wallssuch that the concave surface faces the outer annular wall and theconvex surface faces the inner annular wall. The combustor inner annularliner is disposed about the longitudinal axis, and the inner annularliner has an upstream end. The combustor outer annular liner is disposedconcentric to the combustor inner annular liner and forms a combustionplenum therebetween. The outer annular liner has an upstream end. Thecombustor dome is coupled to and extends between the combustor inner andouter annular liner upstream ends. The curved annular plate is coupledto the combustor inner and outer annular liner upstream ends to form acombustor subplenum therebetween, and the curved annular plate has afirst opening and a second opening formed therein. The first opening isaligned with the deswirl assembly outlet to receive air dischargedtherefrom.

Other independent features and advantages of the preferred deswirlassembly will become apparent from the following detailed description,taken in conjunction with the accompanying drawings which illustrate, byway of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified cross section side view of an exemplarymulti-spool turbofan gas turbine jet engine according to an embodimentof the present invention;

FIG. 2 is a cross section view of a portion of an exemplary combustorthat may be used in the engine of FIG. 1;

FIG. 3 is a cutaway view of a portion of an exemplary deswirl assemblythat may be implemented into the combustor shown in FIG. 2 forwardlooking aft;

FIG. 4 is the portion of the exemplary deswirl assembly shown in FIG. 3aft looking forward; and

FIG. 5 is a top view of the exemplary deswirl assembly shown in FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Before proceeding with the detailed description, it is to be appreciatedthat the described embodiment is not limited to use in conjunction witha particular type of turbine engine. Thus, although the presentembodiment is, for convenience of explanation, depicted and described asbeing implemented in a multi-spool turbofan gas turbine jet engine, itwill be appreciated that it can be implemented in various other types ofturbines, and in various other systems and environments.

An exemplary embodiment of a multi-spool turbofan gas turbine jet engine100 is depicted in FIG. 1, and includes an intake section 102, acompressor section 104, a combustion section 106, a turbine section 108,and an exhaust section 110. The intake section 102 includes a fan 112,which is mounted in a fan case 114. The fan 112 draws air into theintake section 102 and accelerates it. A fraction of the accelerated airexhausted from the fan 112 is directed through a bypass section 116disposed between the fan case 114 and an engine cowl 118, and provides aforward thrust. The remaining fraction of air exhausted from the fan 112is directed into the compressor section 104.

The compressor section 104 includes two compressors, an intermediatepressure compressor 120, and a high pressure compressor 122. Theintermediate pressure compressor 120 raises the pressure of the airdirected into it from the fan 112, and directs the compressed air intothe high pressure compressor 122. The high pressure compressor 122compresses the air still further, and directs the high pressure air intothe combustion section 106. In the combustion section 106, whichincludes an annular combustor 124, the high pressure air is mixed withfuel and combusted. The combusted air is then directed into the turbinesection 108.

The turbine section 108 includes three turbines disposed in axial flowseries, a high pressure turbine 126, an intermediate pressure turbine128, and a low pressure turbine 130. The combusted air from thecombustion section 106 expands through each turbine, causing it torotate. The air is then exhausted through a propulsion nozzle 132disposed in the exhaust section 110, providing additional forwardthrust. As the turbines rotate, each drives equipment in the engine 100via concentrically disposed shafts or spools. Specifically, the highpressure turbine 126 drives the high pressure compressor 122 via a highpressure spool 134, the intermediate pressure turbine 128 drives theintermediate pressure compressor 120 via an intermediate pressure spool136, and the low pressure turbine 130 drives the fan 112 via a lowpressure spool 138.

Turning now to FIG. 2, an exemplary cross section of the area betweenthe high pressure compressor 122 and annular combustor 124 isillustrated. In addition to the compressor 122 and combustor 124, FIG. 2depicts a diffuser 204 and a deswirl assembly 206, each disposed about alongitudinal axis 207. The high pressure compressor 122 is preferably acentrifugal compressor and includes an impeller 208 and a shroud 210disposed in a compressor housing 211. The impeller 208, as alluded toabove, is driven by the high pressure turbine 126 and rotates about thelongitudinal axis 207. The shroud 210 is disposed around the impeller208 and defines an impeller discharge flow passage 212 therewith thatextends radially outwardly.

The diffuser 204 is coupled to the shroud 210 and is configured todecrease the velocity and increase the static pressure of air that isreceived therefrom. In this regard, any one of numerous conventionaldiffusers 204 suitable for operating with a centrifugal compressor maybe employed. In any case, the diffuser 204 includes an inlet 214, anoutlet 216, and a flow path 218 that each communicates with the passage212, and the flow path 218 is configured to direct the received air flowradially outwardly.

The deswirl assembly 206 communicates with the diffuser 204 and isconfigured to substantially remove swirl from air received therefrom, tothereby decrease the Mach number of the air flow. The deswirl assembly206 includes an inner annular wall 220, an outer annular wall 222, andtwo pluralities of vanes 224, 226 disposed therebetween. The walls 220,222 define a flow path 228 that is configured to redirect the air fromits radially outward direction to a radially inward and axiallydownstream direction. In this regard, the walls 220, 222 are formed suchthat the flow path 228 extends between an inlet 230 and outlet 232 in anarc 233 so that when the air exits the outlet 232, it is directed at anangle and toward the longitudinal axis 207 and the annular combustor124. As the angle of the arc 233 is increased the variation of the airangle between the inner wall 220 and out wall 222 is increased.

As briefly mentioned above, the two pluralities of vanes 224, 226 aredisposed between the walls 220, 222. To secure the vanes 224, 226 to theassembly 206, each wall 220, 222 includes two sets of slots 234, 236,238, 240 that are formed in annular patterns along two axial positions.Preferably, the slots 234, 236, 238, 240 are formed downstream of thearc 233. Each of the vanes 224, 226 includes at least a top 242, 244 anda bottom 246, 248 that extend through the slots 234, 236, 238, 240. Thevanes 226, 228 may be secured to the walls 220, 222 in any one ofnumerous fashions, such as, for example, by brazing.

To condition the airflow to a sufficiently low Mach number, each vanepreferably has a substantially identical predetermined shape and ispositioned in the flow path 228 at a predetermined angle relative to thewalls 220, 222. Exemplary vanes 300, which are shown as beingimplemented into the two pluralities of vanes 224, 226, are depicted inFIGS. 3 and 4. As briefly mentioned above, FIG. 3 is a cutaway view ofthe deswirl assembly 200 looking at the vanes 300 from forward to aft,while FIG. 4 is the deswirl assembly shown in FIG. 3 looking at thevanes 300 from aft to forward.

Each vane 300 includes a leading edge 302 and a trailing edge 304. Aconcave pressure surface 306 and a convex suction surface 308 extendbetween the leading and trailing edges 302, 304. The vanes 300preferably each have a uniformly shaped curved axial cross-section fromtop 310 to bottom 312. In this regard, a number of the vanes 300 havingsubstantially identical shapes may be mass produced from a single sheetof material. Specifically, the sheet of material may be suitably pressedinto an appropriate curve shape to form the concave and convex surfaces306, 308 and a plurality of the vanes 300 may be cut from the singlesheet of material.

As mentioned previously, each vane 300 of the two pluralities of vanes224, 226 is disposed at an angle relative to the walls 220, 222.Preferably, the vanes 300 are each placed such that the concave pressuresurface 306 faces outwardly toward the outer annular wall 222 and theconvex suction surface 308 faces inwardly toward the inner annular wall220. Angling the vanes 300 in this preferred embodiment reduces thevariation in air angle between the walls 220, 222. In one exemplaryembodiment, the vanes 300 are disposed such that an angle between theconcave pressure surface 208 the inner annular wall 220 is about 110.8°.However, it will be appreciated that the particular angle at which thevanes 224, 226 are disposed depends on the overall configuration of thewalls 220, 222.

The degree to which the vanes 224, 226 are angled may also determine howthe two pluralities of vanes 224, 226 are placed relative to eachanother. In one example, as shown in FIGS. 3 and 4, the vanes of thefirst plurality of vanes 224 are equally spaced apart from one anotherand the trailing edge of each vane is disposed around a firstcircumferential position 242 around the inner annular wall 220, whilethe vanes of the second plurality of vanes 226 are also equally spacedapart from one another but the leading edge of each is disposed around asecond circumferential position 244. Although the first and secondcircumferential positions 242, 244 are shown in this embodiment asnon-overlapping and the first circumferential position 242 is disposedupstream of the second circumferential position 244, the firstcircumferential position 242 may alternatively be disposed downstream ofthe second circumferential position 244, or may overlap.

Additionally, the second plurality of vanes 226 are preferably staggeredbetween the first plurality of vanes 224. For instance, as shown in FIG.5 viewing the vanes 300 from forward 250 to aft 252, one vane 226 b ofthe second plurality of vanes 226 is preferably disposed between twovanes 224 a, 224 b of the first plurality of vanes 224 and biased towardthe pressure surface 306 of vane 224 b. In one exemplary embodiment, adistance 254 between vane 226 b of the second plurality of vanes 226 andvane 224 b of the first plurality of vanes 224 is about 35% of thedistance 256 between vanes 224 a, 224 b of the first plurality of vanes224. It will be appreciated, however, that the particular distancesbetween all of the vanes may largely depend on the angling thereofrelative to the walls 220, 222.

It will further be appreciated that although two pluralities of vanes226, 228 are included in the embodiment shown in FIG. 2, the deswirlassembly 200 may alternatively only include a single plurality of vanes.In still other embodiments, more than two pluralities of vanes 226, 228may need to be employed.

An improved downcanted deswirl assembly has now been provided thatincludes a plurality of vanes that are configured to aerodynamicallycouple a centrifugal compressor and an axial through-flow combustor.Additionally, the deswirl assembly is relatively inexpensive and simpleto manufacture and is capable of directing and conditioning the airflowing there through for optimal engine performance

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt to a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe appended claims.

1. A deswirl assembly for receiving air flow from a diffuser, thedeswirl assembly comprising: an annular housing including an innerannular wall, an outer annular wall disposed concentric to the innerannular wall, and a flowpath defined therebetween; and a plurality ofvanes disposed in the flowpath in a substantially annular pattern, eachvane having a leading edge, a trailing edge, a convex surface, andconcave surface, each of the convex and concave surfaces extendingbetween the leading and trailing edges, each vane extending between andangled relative to the inner and the outer annular walls such that theconcave surface faces the outer annular wall and the convex surfacefaces the inner annular wall.
 2. The deswirl assembly of claim 1,wherein each vane has an axial cross section shape, and each axial crosssection shape is substantially the same.
 3. The deswirl assembly ofclaim 1, further comprising a second plurality of vanes disposed in theflowpath in a substantially annular pattern downstream of the firstplurality of vanes.
 4. The deswirl assembly of claim 1, wherein thetrailing edges of the vanes of the first plurality of vanes are disposedaround a first circumferential position around the inner annular walland the leading edges of the vanes of the second plurality of vanes aredisposed around a second circumferential position around the innerannular wall.
 5. The deswirl assembly of claim 4, wherein the first andsecond circumferential positions do not overlap.
 6. The deswirl assemblyof claim 4, wherein the first circumferential position is disposeddownstream of the first circumferential position.
 7. The deswirlassembly of claim 4, wherein the vanes of the second plurality of vanesare each staggered between vanes of the first plurality of vanes.
 8. Thedeswirl assembly of claim 7, wherein at least one vane of the firstplurality of vanes is disposed between two vanes of the second pluralityof vanes and a first distance between the at least one vane of the firstplurality of vanes and one of the two vanes of the second plurality ofvanes is less than a second distance between the two vanes of the secondplurality of vanes.
 9. The deswirl assembly of claim 8, wherein thefirst distance is about 35% of the second distance.
 10. A deswirlassembly for receiving air flow from a diffuser, the deswirl assemblycomprising: an annular housing including an inner annular wall, an outerannular wall disposed concentric to the inner annular wall, and aflowpath defined therebetween; a first plurality of vanes disposed inthe flowpath in a substantially annular pattern, each vane having aleading edge, a trailing edge, a convex surface, and concave surface,each of the convex and concave surfaces extending between the leadingand trailing edges, each vane extending between and angled relative tothe inner and the outer annular walls such that the concave surfacefaces the outer annular wall and the convex surface faces the innerannular wall and each vane has an axial cross section shape, each axialcross section shape being substantially the same; and a second pluralityof vanes disposed in the flowpath in a substantially annular patterndownstream of the first plurality of vanes, each vane having a leadingedge, a trailing edge, a convex surface, and concave surface, each ofthe convex and concave surfaces extending between the leading andtrailing edges, each vane extending between and angled relative to theinner and the outer annular walls such that the concave surface facesthe outer annular wall and the convex surface faces the inner annularwall and each vane has an axial cross section shape, each axial crosssection shape being substantially the same.
 11. The deswirl assembly ofclaim 10, wherein the trailing edges of the vanes of the first pluralityof vanes are disposed around a first circumferential position around theinner annular wall and the leading edges of the vanes of the secondplurality of vanes are disposed around a second circumferential positionaround the inner annular wall.
 12. The deswirl assembly of claim 11,wherein the first and second circumferential positions do not overlap.13. The deswirl assembly of claim 11, wherein the first circumferentialposition is disposed downstream of the first circumferential position.14. The deswirl assembly of claim 11, wherein the vanes of the secondplurality of vanes are each staggered between vanes of the firstplurality of vanes.
 15. The deswirl assembly of claim 14, wherein atleast one vane of the first plurality of vanes is disposed between twovanes of the second plurality of vanes and a first distance between theat least one vane of the first plurality of vanes and one of the twovanes of the second plurality of vanes is less than a second distancebetween the two vanes of the second plurality of vanes.
 16. The deswirlassembly of claim 15, wherein the first distance is about 35% of thesecond distance.
 17. A system for aerodynamically coupling air flow froma centrifugal compressor to an axial combustor, the compressor andcombustor disposed about a longitudinal axis, the system comprising: adiffuser having an inlet, an outlet and a flow path extendingtherebetween, the diffuser inlet in flow communication with thecentrifugal compressor, and the diffuser flow path extending radiallyoutward from the longitudinal axis; a deswirl assembly coupled to thediffuser and comprising: an annular housing including an inner annularwall, an outer annular wall disposed concentric to the inner annularwall, and a flowpath defined therebetween, the flow path in flowcommunication with the diffuser outlet to receive air flowing in aradially outward direction, and the deswirl assembly flow pathconfigured to redirect the air in a radially inward and axial directionthrough the deswirl assembly outlet at an angle toward the longitudinalaxis; and a plurality of vanes disposed in the flowpath in asubstantially annular pattern, each vane having a leading edge, atrailing edge, a convex surface, and concave surface, each of the convexand concave surfaces extending between the leading and trailing edges,each vane extending between and angled relative to the inner and theouter annular walls such that the concave surface faces the outerannular wall and the convex surface faces the inner annular wall; acombustor inner annular liner disposed about the longitudinal axis, theinner annular liner having an upstream end; a combustor outer annularliner disposed concentric to the combustor inner annular liner andforming a combustion plenum therebetween, the outer annular liner havingan upstream end; a combustor dome coupled to and extending between thecombustor inner and outer annular liner upstream ends; and a curvedannular plate coupled to the combustor inner and outer annular linerupstream ends to form a combustor subplenum therebetween, the curvedannular plate having a first opening and a second opening formedtherein, the first opening aligned with the deswirl assembly outlet toreceive air discharged therefrom.
 18. The deswirl assembly of claim 17,wherein each vane has an axial cross section shape, and each axial crosssection shape is substantially the same.
 19. The deswirl assembly ofclaim 17, further comprising a second plurality of vanes disposed in theflowpath in a substantially annular pattern downstream of the firstplurality of vanes.
 20. The deswirl assembly of claim 17, wherein: thevanes of the second plurality of vanes are each staggered between vanesof the first plurality of vanes; at least one vane of the firstplurality of vanes is disposed between two vanes of the second pluralityof vanes and a first distance between the at least one vane of the firstplurality of vanes and one of the two vanes of the second plurality ofvanes is less than a second distance between the two vanes of the secondplurality of vanes; and the first distance is about 35% of the seconddistance.